Most children give up their daily nap by the time they are 4 (assuming that they are getting a good quality and quantity of sleep at night) but this does not mean that they are ready to go full throttle from the time they wake until bed time. Even though your child may not need a daily nap they will usually still benefit from some down time and the opportunity to nap if they need to. You will know your child is ready to move from a daily nap to quite time when:

On the days that they nap they then fight getting ready for bed and once they are in bed they have a hard time staying there.

If they do take a nap then they spend an hour (or more) singing, talking and playing before finally falling asleep.